In September 2005 the National Foundation for Educational Research (NFER) in association with the Department for Education and Skills (DfES), the Sutton Trust and the College Board, began a five-year research study to examine the validity of an aptitude test in higher education admissions. This report describes and explores the relationships between scores on the SAT Reasoning Test[TM] (also known in brief as the SAT[R]), attainment measures (A levels and GCSEs [General Certificates of Secondary Education]) and background characteristics of the student sample. The SAT[R] has three measures: Critical Reading, Mathematics and Writing. This report contains nine sections. Following an executive summary, section 2 describes the background to the research and the aims and objectives of the study. Section 3 outlines the methodologies employed and section 4 details the representation and background characteristics of the main SAT[R] sample and the subsequent sub-samples who took part in the student surveys in spring and autumn 2006. Section 5 reports the findings of the analysis of the quantitative data examining the relationships between the SAT[R] and both A level and GCSE attainment. These results are then explored in relation to two key research questions in sections 6 and 7, namely: Can the SAT[R] identify students with the potential to benefit from higher education whose ability is not adequately reflected in their A level results because of their economically or educationally) disadvantaged circumstances (section 6); and can the SAT[R] distinguish helpfully between the most able applicants who get straight As at A level (section 7)? Section 8 presents the findings from the questionnaire surveys and section 9 outlines future potential phases of this research study and suggested milestones when further results will be disseminated. Appended to this report are: (1) Spring 2006 Student Questionnaire; (2) Autumn 2006 Student Questionnaire; (3) SAT[R] Descriptive Statistics; and (4) Functioning of the SAT[R]. (Contains 44 tables and 24 figures.) [This report was produced by the Department of Education and Skills. Additional funding for this project was provided by the Sutton Trust.]